BlobStore does not provide a way to access data in bulk. Code that has been using the 'text' for getQueryInfo() for bulk access to data blobs can no longer be used, because we no longer have rev_text_id to go by in the new (MCR) schema.
As a replacement, we need a way to retrieve a set of data blobs in a way that optimizes the query.
Introduce BlobStore::getBlobBatch( $blobAddresses, $queryFlags = 0 ): string as the batch analog to BlobStore::getBlob. Note that the return value should be associative, indexed by blob address.
- BlobStore::getBlobBatch will have to first see which blobs are already cached, and then only fetch (and then cache) the uncached ones.
- BlobStore::fetchBlob should probably be rewritten to support fetching multiple blobs at once.
- BlobStore::expandBlob will have to be called for each blob individually for now.
- In the future, when we have multiple different BlobStore implementation, the top level "dispatching" BlobStore would have to divide the batch by address schema, and forward each sub-batch to the appropriate BlobStore for that schema. For now though, we can just fail if any of the addresses has a schema different from "tt".